"With Nuclear Weapons, everything has changed, save our way of thinking." So said Albert Einstein, sixty three years ago, following the Hiroshima and Nagasaki bombings at the end of World War II. Having been forced to choose a single game changer, I have turned away from the fascinating scientific developments I might like to see, and will instead focus on the one game changer that I will hopefully never directly witness, but nevertheless expect will occur during my lifetime: the use of nuclear weapons against a civilian population. Whether used by one government against the population of another, or by a terrorist group, the detonation of even a small nuclear explosive, similar in size, for example, to the one that destroyed hiroshima, would produce an impact on the economies, politics, and lifestyles of the first world in a way that would make the impact of 9/11 seem trivial. I believe the danger of nuclear weapons use remains one of the biggest dangers of this century. It is remarkable that we have gone over 60 years without their use, but the clock is ticking. I fear that Einstein's admonition remains just as true today as it did then, and I that we are unlikely to go another half century with impunity, at least without confronting the need for a global program of disarmament that goes far beyond the present current Nuclear Non-Proliferation, and strategic arms treaties.

Following forty years of Mutually Assured Destruction, with the two Superpowers like two scorpions in a bottle, each held at bay by the certainty of the destruction that would occur at the first whiff of nuclear aggression on the part of the other, we have become complacent. Two generations have come to maturity in a world where nuclear weapons have not been used. The Nuclear Non-Proliferation Treaty has been largely ignored, not just by nascent nuclear states like North Korea, or India and Pakistan, or pre-nuclear wannabies like Iran. Together the United States and Russia possess 26,000 of the world's 27,000 known nuclear warheads. This in spite of the NPT's strict requirement for these countries to significantly reduce their arsenals. Each country has perhaps 1000 warheads on hair trigger full alert. This in spite of the fact that there is no strategic utility at the current time associated with possessing so many nuclear weapons on alert.

Ultimately, what so concerned Einstein, and is of equal concern today, is the fact that first use of nuclear weapons cannot be justified on moral or strategic grounds. Nevertheless, it may surprise some people to learn that the United States has no strict anti-first-use policy. In fact, in its 2002 Nuclear Posture Review, the U.S. declared that nuclear weapons "provide credible military options to deter a wide range of threats" including "surprising military developments."

And while we spend $10 billion/yr on flawed ballistic missile defense systems against currently non-existent threats, the slow effort to disarm means that thousands of nuclear weapons remain in regions that are unstable, and which could, in principle, be accessed by well organized and well financed terrorist groups. We have not spent a noticeable fraction of the money spent supposedly defending against ballistic missiles instead outfitting ports and airports to detect against possible nuclear devices smuggled into this country in containers.

Will it take a nuclear detonation used against a civilian population to stir a change in thinking? The havoc wreaked on what we now call the civilized world, no matter where a nuclear confrontation takes place, would be orders of magnitude greater than that which we have experienced since the Second World War. Moreover, as recent calculations have demonstrated, even a limited nuclear exchange between, say India and Pakistan, could have a significant global impact for almost a decade on world climates and growing seasons.

I sincerely hope that whatever initiates a global realization that the existence of large nuclear stockpiles throughout the world is a threat to everyone on the planet, changing the current blind business-as-usual mentality permeating global strategic planning, does not result from a nuclear tragedy. But physics has taught me that the world is the way it is whether we like it or not. And my gut tells me that to continue to ignore the likelihood that a game changer that exceeds our worst nightmares will occur in this century is merely one way to encourage that possibility.